(1) Field of the Invention
The present invention relates to the preparation of chemically modified polysaccharides which have carboxylic acid moieties and which are water dispersible and useful as carriers. The composition provides a timed release of the chemicals in pharmaceuticals, veterinary medicaments and cosmetics. The present invention also provides a process for the preparation of chemically modified polysaccharides.
(2) Description of the Related Art
The prior art describes various compositions derived from natural carbohydrates for use as carriers and processes for the preparation of modified carbohydrates, particularly cellulose. Natural polymers and gums have been used in pharmaceutical formulations of sustained-release carriers, and modified celluloses, carboxy methylcellulose (CMC) and modified methyl cellulose (MMC) are found in a large number of formulations as viscosity enhancers. Because of their wide acceptance of these modified natural polymers, pharmaceutical companies are interested in the use of modified natural polymers for their drug delivery systems. Natural polymers with gelling properties that have been successfully used in topical formulations include gellan gum and carrageenans. Topical formulations with gelling properties afford increased bioavailability of certain drugs.